1. Field of the Invention
This invention relates to a slide fastener slider of the type in which, after a slider body has been produced, a pull tab is attached to the slider so as to be free from being accidentally removed off the slider body.
2. Description of the Related Art
Many slide fastener sliders of the above-mentioned type are currently known. For example, Japanese Patent Publication No. Hei 1-14761 discloses a slider which has a cantilevered arch-shape attachment lug integrally standing on an upper wing of a slider body at its front end and extending toward its rear end for holding an axle of a pull tab between the attachment lug and the upper wing, a recess formed in the upper surface of the upper wing in confronting relation to the rear end of the attachment lug for passage of the attaching ring of the pull tab, and a resilient member supported by the slider body or the attachment lug for normally closing a gap between the upper wing and the rear end of the attachment lug. In production, for attaching the pull tab to the slider body, the axle of the pull tub is inserted through the gap as it deforms the resilient member closing the gap.
Japanese Patent Publication No. Hei 3-8761 discloses a slider which has a cantilevered arch-shape attachment lug integrally standing on an upper wing of a slider body at its front end and extending toward its rear end for holding an axle of a pull tab between the attachment lug and the upper wing, a gap defined between the rear end of the attaching lug and the upper wing, a gap-closing member slidably received in a longitudinal groove in the upper wing for movement between a closed position near the rear end of the attachment lug and an open position away from the rear end of the attachment lug, and a spring received in the longitudinal groove for normally urging the gap-closing member toward the closed position.
Republic of China Patent No. 272386 discloses a slider which has, as shown in FIG. 7 of the accompanying drawings, a cantilevered arch-shape attachment lug 9' standing integrally on an upper wing 3' of a slider body 1' at its rear end 11' and extending toward its front end 10' for holding an attaching ring of a pull tab (not illustrated) between the attachment lug 9' and the upper wing 3', a bottom-closed vertical groove 13' formed in the front surface of a guide post 13', a trapezoidal stop 18' vertically slidably received in the vertical groove 13', and a coil spring 20' disposed in the vertical groove 13' for normally urging the stop 18' upward against a lower surface 9a' of the front end of the attachment lug 9'. In production, after the stop 18' and the spring 20' have been inserted in the vertical groove 13', the front side of the vertical groove 13' is closed with a closure plate 21' to be fixed by clenching a pair of opposite side flanges F'. For attaching the pull tab to the attachment lug 9', the stop 18' is pushed downward away from the front end of the attachment lug 9' by the attaching ring of the pull tab so as to allow the attaching ring to pass through a gap 15' between the front end of the attachment lug 9' and the upper surface of the upper wing 3'.
However, in the slider disclosed in the first-named publication, partly since the pulling force of the pull tab acts directly on the resilient member and partly since the resilient member is supported by the attachment lug, a stable pull-tab-catching mechanism cannot be achieved. Further, since the gap between the rear end of the attachment lug and the upper surface of the slider body is substantially equal to the thickness of the axle of the pull tab, the axle pushes the resilient member from outside against the bias of the resilient member when the pull tab is pulled laterally in a horizontal posture and, as a result, the pull tab might inadvertently be removed off the slider body via the gap. And it is not possible to make the recess deeper so as to catch the resilient member well because the thickness of the upper wing at its rear end is particularly limited.
Also in the slider disclosed in the second-named publication, partly since the attachment lug stands on the upper surface of the upper wing at its front end and extends toward its rear end and partly since the gap-closing member is disposed at the rear end of the upper wing, a string pull-tab-catching mechanism cannot be achieved. Further, likewise the first-named publication, since the gap between the rear end of the attachment lug and the upper wing of the slider body is substantially equal to the thickness of the axle of the pull tab, the axle pushes the resilient member at its rear end portion from outside against the bias of the resilient member when the pull tab is pulled laterally in a horizontal posture and, as a result, the pull tab might inadvertently be removed off the slider body via the gap.
In the slider disclosed in the last-named publication (FIG. 7), the gap-closing mechanism is mounted in the guide post 5' at the front end of the slider body 1', which is successful in making the mechanism itself stronger. However, in this slider, likewise the previous sliders, the attaching ring of the pull tab pushes the stop 18' from outside against the resilience of the spring 20' when the pull tab is pulled laterally in a horizontal posture and, as a result, the pull tab might inadvertently be removed off the slider body 1' via the gap 15'. Further, since the stop 18' and the spring 20' are inserted into the guide post 5' from its front side, this slider is not suitable to automated assembling.